[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 260003
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT JUL 25 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 18N44W TO 6N40W MOVING W 15-20 KT.
THIS WAVE IS ALONG THE LEADING EDGE OF A DEEP LAYER MOISTURE
MAXIMUM AS OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. VISIBLE
SATELLITE IMAGERY INDICATES LOW LEVEL CYCLONIC CURVATURE MAINLY
NEAR 12N43W. DRY SAHARAN AIR IS LIMITING DEEP CONVECTION NEAR
THE WAVE.

TROPICAL WAVE IS ALONG 83W S OF 21N MOVING NEAR W 20 KT. THIS
WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYER MOISTURE
MAXIMUM AS OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY.
SUBSIDENCE. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS
W OF THE WAVE AXIS OVER CENTRAL AMERICA FROM 11N-16N BETWEEN
83W-89W.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 14N16W 9N37W 11N54W 10N63W.
ISOLATED MODERATE CONVECTION IS ALONG THE COAST OF WEST AFRICA
FROM 8N-10N BETWEEN 14W-20W. SIMILAR CONVECTION IS FROM 8N-12N
BETWEEN 28W-38W. SCATTERED MODERATE CONVECTION FROM 9N-12N
BETWEEN 48W-51W.

...DISCUSSION...

GULF OF MEXICO...
A 1020 MB HIGH IS CENTERED OVER THE NE GULF OF MEXICO NEAR
28N87W. 5-10 KT ANTICYCLONIC SURFACE WINDS REMAIN OVER THE E
GULF E OF 90W WHILE 5-10 KT SOUTHERLY WINDS ARE OVER THE W GULF.
ELSEWHERE...PATCHES OF SCATTERED MODERATE CONVECTION HAVE
ADVECTED OVER FLORIDA...THE YUCATAN PENINSULA...AND THE S GULF S
OF 27N...FROM THE SW ATLANTIC AND W CARIBBEAN. THIS CONVECTION
MAY BE ASSOCIATED WITH TROPICAL MOISTURE MOVING RAPIDLY WEST. IN
THE UPPER LEVELS...AN UPPER LEVEL LOW IS CENTERED OVER THE NW
GULF NEAR 27N93W. UPPER LEVEL DIFFLUENCE SE OF THE CENTER IS
HELPING TO PRODUCE CONVECTION OVER THE SE GULF AND FLORIDA. A
SIGNIFICANT AMOUNT OF UPPER LEVEL MOISTURE COVERS THE GULF.
EXPECT...LITTLE CHANGE OVER THE NEXT 24 HOURS.

CARIBBEAN SEA...
A TROPICAL WAVE IS OVER THE W CARIBBEAN. SEE ABOVE. SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION IS ALSO OVER W CUBA FROM
21N-23N BETWEEN 78W-84W...AND OVER THE YUCATAN PENINSULA FROM
17N-21N BETWEEN 87W-91W. THE REMAINDER OF THE CARIBBEAN E OF 80W
IS DOMINATED BY DRY AIR AND IS VOID OF CONVECTION. ISOLATED
SHOWERS ARE HOWEVER OVER PUERTO RICO AND THE LEEWARD ISLANDS
FROM 17N-20N BETWEEN 60W-67W. FRESH TO STRONG TRADEWINDS ARE
OVER THE CARIBBEAN WITH THE STRONGEST WINDS UP TO 30 KT ARE NEAR
THE COAST OF COLUMBIA. IN THE UPPER LEVELS...A SMALL UPPER LEVEL
HIGH IS CENTERED OVER HONDURAS WHILE EASTERLY UPPER LEVEL FLOW
AND STRONG SUBSIDENCE IS OVER THE CENTRAL AND E CARIBBEAN E OF
80W. EXPECT...TROPICAL MOISTURE WITH CONVECTION TO ADVECT OVER
THE WINDWARD ISLANDS OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...
SCATTERED MODERATE CONVECTION IS OVER THE N BAHAMAS FROM 23N-27N
BETWEEN 76W-80W. A 1028 MB HIGH IS CENTERED OVER THE CENTRAL
ATLANTIC NEAR 33N37W. A RIDGE AXIS EXTENDS W TO E OF THE BAHAMAS
NEAR 27N75W.  A SURFACE TROUGH IS OVER THE CENTRAL ATLANTIC FROM
26N45W TO 18N49W. THIS TROUGH DELINEATES A SURGE OF TROPICAL
MOISTURE THAT HAS BROKEN AWAY FROM THE TROPICAL WAVE FURTHER S.
IN THE UPPER LEVELS...AN UPPER LEVEL RIDGE IS OVER THE W
ATLANTIC W OF 70W. AN UPPER LEVEL LOW IS FURTHER E CENTERED NEAR
28N60W. A LARGE UPPER LEVEL HIGH IS CENTERED OVER THE CENTRAL
ATLANTIC NEAR 20N43W. ANOTHER UPPER LEVEL HIGH IS CENTERED OVER
THE CANARY ISLANDS NEAR 28N12W. EXPECT...TROPICAL CONVECTION
ALONG THE ITCZ...AND WITH THE TROPICAL WAVE OVER THE NEXT 24
HOURS.

$$
FORMOSA





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